已知弧长186弦长180,求半径和弦高.

已知弧长C=186弦长L=180,求半径R和弦高H?
弧所对的圆心角为A.
Rn+1=(1+(L-2*Rn*SIN(C/(2*Rn)))/(L-C*COS(C/(2*Rn))))*Rn
R0=200
R1=209.18
R2=210.34
R3=210.36
R4=210.36
R=210.36
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((180/2)/210.36)
=50.66度
H=R-R*COS(A/2)
=210.36-210.36*COS(50.66/2)
=20.225